Support typings in package.json by auto-generating immutable-nonambie…

[danielearwicker]

As noted in #734 it is now possible to tell TypeScript where to find type defs in package.json by setting the typings property.

However the immutable.d.ts file is an ambient module (exports a module path name as a string). This is why pull request #779 didn't work. What is needed is a plain module that directly exports all the members of the namespace (there is no need for a top-level layer of wrapping as that is supplied by the external module).

There doesn't appear to be a way to define a module in one file and reuse it in both ambient and non-ambient contexts. So I've added a trivial bit of regex find-and-remove to the existing gulp task 'typedefs' to generate dist/immutable-nonambient.d.ts, and amended package.json to expose via the typings property.

This means immutable.d.ts can continue to be maintained as it is, as long as the two significant bits of wrapping are left as they are. Maybe they should have comments around them in immutable.d.ts to warn people against changing them?

Another option is to make the non-ambient version be definitive, as it only needs to be prefixed/suffixed as follows to make the equivalent of the existing ambient version:

declare module Immutable {

    // non-ambient file content goes here
}

declare module "immutable" {
  export = Immutable
}

Also I haven't removed the typescript property in package.json in case it is important for backward compatibility. It appears to be harmless.

[leebyron]

Great, thank you for this!